Calculating the value of e: Difference between revisions

=={{header|UNIX Shell}}==

<syntaxhighlight lang="sh"># POSIX requires "signed long" for shell arithmetic, so assume to have

# at least 31 bits available, and do 2:29 bits fixed point arithmetic

prec=29 one=$((1 << prec))

e=$one fact=1 n=0

while [ $fact -lt $one ]

do

e=$((one / (fact *= (n += 1)) + e))

done

# convert to decimal string

n=9 str=$((e >> prec)). mask=$((one + one - 1))

while [ $((n -= 1)) -ne 0 ]

do

str=$str$(((e = ((mask >>= 1) & e) * 5) >> (prec -= 1)))

done

echo "$str"

</syntaxhighlight>

{{out}}

<pre>2.71828182</pre>